Multidrug resistant organisms are increasingly prevalent in nosocomial and community settings. Novel antibiotics with new mechanisms of action are needed to combat the impending public health crisis of antibiotic-resistant pathogens like Staphylococcus aureus, Enterococcus faecium, Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumanii, and Klebsiella pneumoniae, among others. The added threat of bioterrorism with an agent most certainly engineered to be resistant to currently available antibiotics makes this need particularly acute. The long-term goal of this project is to address this need by developing a pipeline of novel broad spectrum antimicrobial compounds. Most antibiotics in use today have come from natural products obtained from less than 1% of microbial species cultivable by conventional methods. The remaining 99% of as yet uncultivated species represent essentially an unlimited diversity of microorganisms to discover novel antibiotics. In this Phase I project we aim to access some of these "missing" species. We will develop a method to isolate slow growing and rare species that until now remained uncultivated and unexplored. It has been conventional but unproven wisdom that these bacteria are unsuited for a drug discovery pipeline because the rate of their discovery is low, and large scale growth is problematic. Here we present evidence that neither assumption holds, and that in fact, slow growing and rare species can be an excellent resource of antimicrobial discovery. The specific aims for this project are: Aim 1: Develop long-term incubation method to cultivate slower growing and rare cells;Aim 2: Scale up growth of novel species and screen for antimicrobial activity;Aim 3: Investigate the chemical novelty of the discovered activities. The data in Phase I will demonstrate whether slow growing isolates represent novel species that can be isolated in large numbers and efficiently converted into fast growing cultures and whether these species produce potentially novel antibiotics. The results in Phase I will will inform our cultivation strategy in Phase II, in which we will establish a large-scale drug discovery pipeline sufficient for discovery of novel broad-spectrum antibiotics from a novel pool of microbial diversity. PUBLIC HEALTH RELEVANCE: The threat of increased antibiotic resistance in bacteria urgently requires development of novel antimicrobials. This proposal aims to develop a new pipeline for discovery of antibiotics from novel, previously uncultivated microorganisms to combat this impending public health crisis.